Confirmed the size of “Ofelia” and made new gas discovery

Confirmed the size of "Ofelia" and made new gas discovery

The drilling was carried out by the Deepsea Yantai rig.

15/12/2023 Drilling of the appraisal well on the "Ofelia" discovery in the North Sea confirmed already proven volumes in the main reservoir. The operator, Neptune, also drilled a sidetrack that led to a gas discovery.

Well 35/6-4 S in production licence 929 confirmed the oil and gas volumes in "Ofelia". The 35/6-4 A sidetrack resulted in a new gas discovery. Preliminary estimates place the size of the new discovery between 1.8-3 billion standard cubic meters (Sm3) of recoverable gas.

The total size of both discoveries is estimated at between 4.3-8.3 million Sm3 of recoverable oil equivalent (27-52 million barrels). The discoveries are located near the Gjøa field, also operated by Neptune. The licence is considering connecting the discoveries to existing infrastructure on Gjøa.

This is the third time Neptune has made a discovery in chalk reservoir rocks in this area, and this can contribute to increased production from the Gjøa platform.

Production licence 929 was awarded in the Awards in Predefined Areas (APA) in 2018.

Geological information

The 35/6-3 S (Ofelia) discovery was proven in Lower Cretaceous reservoir rocks in the Agat Formation in 2022. Prior to the drilling of appraisal well 35/6-4 S, the operator's resource estimate for the discovery was between 2.5-6.2 million Sm3 of recoverable oil equivalent.

The objective of well 35/6-4 S was to delineate the 35/6-3 S discovery in Lower Cretaceous reservoir rocks in the Agat Formation.
The objective of well 35/6-4 A was to prove petroleum in Upper Cretaceous reservoir rocks in the Kyrre Formation.

Well 35/6-4 S encountered a thin gas column and a 35-metre oil column in the Agat Formation in sandstone reservoirs of about 25 metres with moderate to good reservoir quality. The oil/water contact was not encountered.
Well 35/6-4 A encountered a 32-metre gas column in the Kyrre Formation, distributed between three sandstone layers totalling 30 metres with extremely good to very good reservoir quality. A gas/water contact was encountered in the lowermost sand, 1905 metres below sea level.

The wells were not formation-tested, but extensive data acquisition and sampling were carried out.

Appraisal well 35/6-4 S was drilled to a vertical depth of 2695 metres and a measured depth of 3167 metres below sea level, and was terminated in basement rock. Appraisal well 35/6-4 A was drilled to a vertical depth of 1964 metres and a measured depth of 2352 metres below sea level, and was terminated in the Kyrre Formation in the Upper Cretaceous.

Water depth at the site is 331 metres. The wells have been plugged and abandoned.

Updated: 15/12/2023

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